100A 4 Pole 4 Module 100mA Time Delay RCD 100-100-4TD

Protek’s RCDs are Type AC and conform to BSEN 61008. Tripping is ensured for residual sinusoidal current alternating currents whether the fault is suddenly applied or is a slow rising fault.

RCDs are designed to prevent electrocution by detecting the leakage current, which can be far smaller (typically 5 - 30 milliamperes) than the currents needed to operate conventional circuit breakers or fuses (several amperes). RCDs are intended to operate within 25-40 milliseconds, before electric shock can drive the heart into ventricular fibrillation, the most common cause of death through electric shock.

RCDs operate by measuring the current balance between two conductors using a differential current transformer. This measures the difference between the current flowing out the live conductor and that returning through the neutral conductor. If these do not sum to zero, there is a leakage of current to somewhere else (to earth/ground, or to another circuit), and the device will open its contacts.

Residual current detection is complementary to over-current detection. Residual current detection cannot provide protection for overload or short-circuit currents.